The present invention relates in general to expansion joint seal assemblies of the type used for sealing an expansion joint space or gap in a roadway, bridge or the like against the intrusion of dirt, water, and other debris and contaminants as for example might be encountered by expansion joints in roadway and bridge installations. More specifically, the present invention relates to an elastomeric expansion seal assembly formed of a shaped elastomeric diaphragm seal member and a pair of elongated extruded metal anchor channels installed on opposite sides of the gap or space to be protected and embedded in concrete slabs to achieve anchoring of the diaphragm seal member between the anchor channels.
A persistent problem which has been encountered in connection with expansion joint sealing strip assemblies of the type to which the present invention is related is that the retaining or mounting or anchoring bead portion of the flexible or elastomeric seal member becomes dislodged from one of the edge members forming the anchor formations for the ends of the sealing diaphragm over part or all of the longitudinal extent of the joint, so that the seal no longer remains watertight and consequently ceases to perform a primary function for which it was provided. Numerous proposals have been made for variations in design of the edge bead formations or mounting portions along opposite edges of the seal strip of expansion joint seal assemblies seeking to minimize the possibility of failure of the anchoring or edge retaining portions by dislodging of the seal strip member from the edge retaining formation of the assembly. In the case of expansion joint sealing strip assemblies having mounting beads along the longitudinal edges thereof to be mounted in correspondingly shaped cavities of the edge retaining or anchoring components, a number of specific problems have been recognized. In many of the prior art expansion joint sealing strip assemblies, it has been very difficult to shape the metal edge retaining or anchoring members with a cavity for receiving the mounting beads along the edge of the sealing strip with a cavity of properly precise cross-section which includes the desired degree of high-tolerance along the length of the edge retaining member. Frequently, the manufacture of such edge retaining metal devices as a metal extrusion with a shaped cavity therein requires that the cavity be of precisely uniform cross-section throughout the entire length of about a 16 foot or more longitudinal length of the extrusion, as may be required for a road or bridge joint, and in such lengths, it has been found that the extruding of the edge retaining member fails to maintain appropriate uniformity in the cross-sectional dimensions of the cavity along the entire longitudinal span required. However, it has been possible to maintain the desired high-tolerance with respect to the configuration and cross-sectional dimensions of the retaining bead or edge portion of the expansion joint sealing strip. The discrepancy in the extent to which high-tolerances can be maintained in the shape of the cavity and the shape of the bead formation results, of course, in frequent instances of the bead becoming more easily dislodged from the cavity of the retaining member.
Additionally, problems have been encountered in developing optimum designs for the shape of the retaining beads along the edges of the sealing strip to facilitate insertion of the bead into the cavity of the bead retaining anchor or edge members. While efforts have been made to facilitate the introduction of beads into the retaining cavities by making the beads hollow, permitting them to be more readily compressed and deformed to be received in the retaining cavity, this also enables the hollow edge bead formations to be more easily deformed and pulled out of the retaining cavities of the retaining channel or anchor members under various conditions, particularly as hard or solid contaminants work into the cavity and as water intrudes into the cavity and freezes.
Additionally, as cross-sectional design configurations of the edge retaining beads have been modified to resist intrusion of solid contaminants and water intrusion into the anchor member cavity, it has become more and more difficult to manually extract the retaining bead portions of the sealing strips from the retaining cavities when it is desired to replace or service the sealing strips for the expansion joints. While efforts have been designed to facilitate the provision of snap-in-action insertion of the sealing strip edge formations into the retaining cavities, it has been discovered that the modifications of the configuration of the snap-in retaining beads to enable them to more easily snapped-in also carries the disadvantage that they can be more easily pushed out. Also, while the configuration of the sealing material, usually made of an elastomer, such as a high-grade neoprene or the like, is such as to allow the retaining bead edge portions of the elastomer sealing strip to move apart and together at skew angles, many shapes designed to permit the strip to open and close on skew angles are such that tearing and undue force on the sealing strip is encountered.
Accordingly, an object of the present invention is the provision of a novel elastomeric expansion joint sealing strip assembly having mounting or retaining bead formations along the longitudinal edges of the sealing strip insertable into a shaped cavity of each of a pair of opposite channel anchor members, wherein the retaining beads and the cavity are of novel coactive configuration correlated with corrugations or folds of the sealing strip to facilitate insertion and extraction of the retaining beads from the cavities of the anchor channel members.
Another object of the present invention is the provision of a novel elastomeric expansion joint sealing strip assembly as described in the immediately preceding paragraph, provided with initially hollow retaining bead formations along the longitudinal edges of the sealing strip portion which may be filled with semi-rigid material to facilitate locking of the retaining bead formations in the cavities of the anchor channel members, but which are also provided with tabs which coact with portions of the cavities and retaining bead formations of novel shape facilitating extraction of the retaining bead formations from the cavities when it is desired to replace or service the sealing strips.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.